Sleep-Disordered Breathing (SDB) is a general term for a sleep disorder with apneas and hypopneas. Obstructive Sleep Apnea (OSA) is an example of such a sleep disorder. Sullivan invented treatment of OSA with nasal Continuous Positive Airway Pressure (CPAP). See U.S. Pat. No. 4,944,310 (Sullivan). An apparatus for CPAP treatment typically includes: (i) a source of air at positive pressure, such as a blower, flow generator, or other positive airway pressure (PAP) device; (ii) an air delivery conduit; and (iii) a patient interface, such as a mask. The patient interface typically is connected to the patient with headgear including, for example, a series of elastic straps. At least a portion of the headgear is in contact with the patient's skin, typically on the patient's face. Patients wear the apparatus while sleeping.
A basic CPAP device may provide a supply of air at a generally fixed pressure in the range of 4-20 cmH2O. A more advanced CPAP device such as ResMed's AUTOSET SPIRIT can monitor the patient's breathing, determine the shape of the breath waveform, detect the presence of snoring, apneas, and hypopneas, and also adjust the treatment pressure. See U.S. Pat. No. 5,704,345 (Berthon-Jones), the entire contents of which is incorporated herein by reference.
Diabetes is a disease characterized by an elevated level of glucose in the blood and in the urine. When blood sugar extremes—both high (hyperglycemia) and low (hypoglycemia)—are not treated, a patient can fall into a diabetic coma. The most common cause of diabetic coma is hypoglycemia. This is caused by excessive treatment with insulin relative to food intake and physical activity. Research indicates that the frequency of severe hypoglycemia is about 1.9 and 2.6 episodes per patient per year for Type 1 and Type 2 diabetes patients, respectively, with approximately 50% of these episodes occurring during sleep. There is evidence that the fear of a hypoglycemic episode significantly affects patient outcomes, such as glycemic control and management, self-treatment modifications, and post-episode lifestyle infringements (see Leiter et al. 2005, Canadian J. Diabetes; 29:186-192). Recent studies have indicated that about 30% of diabetic patients also have OSA (Meslier et al, Eur. Resp. J., 22(1):156-160), and there is emerging data indicating that effective treatment of OSA with n-CPAP significantly improves glucose metabolism.
Given that many diabetic patients will require treatment for their OSA or other SDB, certain example embodiments of the present invention are directed towards improving patient outcomes by providing methods and apparatuses that can reduce the patients' fear of hypoglycemia and/or other diabetes-related events.